Neovim/Template goto definition returns error: index out of range

[catgoose]

Before you begin

❯ templ version
v0.2.778

Describe the bug
Attempting to use Neovim templ LSP to go to the definition of a templ template inside of a .templ file will produce error:

Error executing vim.schedule lua callback: /usr/local/share/nvim/runtime/lua/vim/lsp/util.lua:17
98: index out of range
stack traceback:
        [C]: in function '_str_byteindex_enc'
        /usr/local/share/nvim/runtime/lua/vim/lsp/util.lua:1798: in function 'locations_to_items
'
        /usr/local/share/nvim/runtime/lua/vim/lsp/handlers.lua:436: in function 'handler'
        /usr/local/share/nvim/runtime/lua/vim/lsp/client.lua:687: in function ''
        vim/_editor.lua: in function <vim/_editor.lua:0>
Press ENTER or type command to continue

To Reproduce
https://github.com/catgoose/templ_issue_repro

Follow steps in readme

Expected behavior
Issuing vim.lsp.buf.definition on a templ template reference in a templ file should go to that templates definition

Screenshots

Taken from the reproduction repo above

Logs
Log file templ.log included in repro repo

templ info output

❯ templ info
(✓) os [ goos=linux goarch=amd64 ]
(✓) go [ location=/usr/local/go/bin/go version=go version go1.23.1 linux/amd64 ]
(✓) gopls [ location=/home/catgoose/go/bin/gopls version=golang.org/x/tools/gopls v0.16.2 ]
(✓) templ [ location=/home/catgoose/go/bin/templ version=v0.2.778 ]

Desktop (please complete the following information):

• OS: Ubuntu 24.04.1
• templ version: v0.2.778
• Go version: go version go1.23.1 linux/amd64
• gopls version: golang.org/x/tools/gopls v0.16.2

Additional context
This seems to have been fixed here #893 but the issue persists
Reported here catgoose/templ-goto-definition#1

[a-h]

Thanks for providing a good reproduction. I had to run :set filetype=templ to get the LSP to attach to the buffer, but once I'd done that, I was able to type the default leader followed by gd to trigger the error (\gd).

I got similar logs as to the one in the repo. These are the important lines.

{"level":"info","ts":"2024-09-09T08:33:38+01:00","caller":"proxy/server.go:541","msg":"client -> server: Definition"}
{"level":"info","ts":"2024-09-09T08:33:38+01:00","caller":"proxy/server.go:71","msg":"updatePosition: found","uri":"file:///Users/adrian/github.com/catgoose/templ_issue_repro/views/index.templ","fromTempl":"6:5","toGo":"33:24"}
{"level":"info","ts":"2024-09-09T08:33:38+01:00","caller":"proxy/server.go:564","msg":"client -> server: Definition end"}

In particular this:

{
   "level":"info",
   "ts":"2024-09-09T08:33:38+01:00",
   "caller":"proxy/server.go:71",
   "msg":"updatePosition: found",
   "uri":"file:///Users/adrian/github.com/catgoose/templ_issue_repro/views/index.templ",
   "fromTempl":"6:5",
   "toGo":"33:24"
}

Note that templ believes that line 6, col 5 in the templ file maps to the line 33, col 24 in the Go code.

I can verify this in the templ LSP web server. Note the highlighted (yellow) section.

This looks correct.

I had updated my version of gopls as per your reproduction instructions. When I put it back, the problem went away, so I went back through the history of gopls to find when the error started happening.

If I install gopls v0.15.2 (go install golang.org/x/tools/gopls@v0.15.2), it works OK, but if I use v0.15.3 or greater (go install golang.org/x/tools/gopls@v0.15.3), then I get the error.

I'm not sure what changed between those versions. Maybe a reshape of the JSON structures to support a later version of the LSP spec? But, progress on reproduction.

[a-h]

Comparison of gopls: golang/tools@gopls/v0.15.2...gopls/v0.15.3

[catgoose]

What is strange is such as with #893 if you open the file for the target definition, then go to definition works.

content.templ buffer not open, error presented when trying goto definition in index.templ:

{
  "level": "info",
  "ts": "2024-09-09T06:43:13-05:00",
  "caller": "proxy/server.go:541",
  "msg": "client -> server: Definition"
}
{
  "level": "info",
  "ts": "2024-09-09T06:43:13-05:00",
  "caller": "proxy/server.go:71",
  "msg": "updatePosition: found",
  "uri": "file:///home/catgoose/git/templ_issue_repro/views/index.templ",
  "fromTempl": "6:4",
  "toGo": "33:23"
}
{
  "level": "info",
  "ts": "2024-09-09T06:43:13-05:00",
  "caller": "proxy/server.go:564",
  "msg": "client -> server: Definition end"
}

Opened content.templ:

{
  "level": "info",
  "ts": "2024-09-09T06:45:19-05:00",
  "caller": "proxy/server.go:650",
  "msg": "client -> server: DidOpen",
  "uri": "file:///home/catgoose/git/templ_issue_repro/views/content.templ"
}
{
  "level": "info",
  "ts": "2024-09-09T06:45:19-05:00",
  "caller": "proxy/server.go:674",
  "msg": "setting source map cache contents",
  "uri": "file:///home/catgoose/git/templ_issue_repro/views/content.templ"
}
{
  "level": "info",
  "ts": "2024-09-09T06:45:19-05:00",
  "caller": "proxy/server.go:681",
  "msg": "client -> server: DidOpen end"
}
{
  "level": "info",
  "ts": "2024-09-09T06:45:19-05:00",
  "caller": "proxy/client.go:52",
  "msg": "client <- server: PublishDiagnostics"
}

Now try goto definition in Index.templ on Content

{
  "level": "info",
  "ts": "2024-09-09T06:46:34-05:00",
  "caller": "proxy/server.go:541",
  "msg": "client -> server: Definition"
}
{
  "level": "info",
  "ts": "2024-09-09T06:46:34-05:00",
  "caller": "proxy/server.go:71",
  "msg": "updatePosition: found",
  "uri": "file:///home/catgoose/git/templ_issue_repro/views/index.templ",
  "fromTempl": "6:4",
  "toGo": "33:23"
}
{
  "level": "info",
  "ts": "2024-09-09T06:46:35-05:00",
  "caller": "proxy/server.go:564",
  "msg": "client -> server: Definition end"
}

So it seems to me that gopls is trying to target the wrong position, but if the buffer is open it catches it self and says "that's not the right line, but I can see it's on this line because I'm attached to that buffer so we will return that position"

[a-h]

I just noticed that!

The issue is that the gopls server is telling templ that the definition exists in a Go file that templ hasn't got in its sourceMap that maps from templ positions to Go code positions, so it's returning a position in the file that might not exist instead.

The issue is in the convertGoRangeToTemplRange function. If the Go range is in a *_templ.go file that it doesn't know about, it probably needs to load the associated *.templ file, and populate the source map for that file, then everything should work correctly.

However, I'm not sure if we can rely on loading the file from the URI... one way to find out...

[tris203]

It will no longer error in Neovim nighly (as of last night, after this PR neovim/neovim#30288)
And it won't error in Stable after the next release as the fix got backported.

However, it still maps to the wrong spot if the source map doesn't exist.
I see where the problem is in convertGoRangeToTemplRange.
Happy to take a look shortly if you want me to @a-h

[axadrn]

It will no longer error in Neovim nighly (as of last night, after this PR neovim/neovim#30288) And it won't error in Stable after the next release as the fix got backported.

However, it still maps to the wrong spot if the source map doesn't exist. I see where the problem is in convertGoRangeToTemplRange. Happy to take a look shortly if you want me to @a-h

Yes, I can confirm, the problem disappeared with the nightly version!

[a-h]

You went deep on this one @tris203 - well done! 😁

[tris203]

You went deep on this one @tris203 - well done! 😁

Thanks. The error is gone in neovim
But it will still you to the wrong line in the file until #912 is complete

[catgoose]

@a-h Could we get a release made with these changes? Thanks!